The media gateway controller (MGC) and the media gateway (MG) are two key components on a packet network where services are separated from bearers. The MGC is responsible for service control, and the MG is responsible for media bearing so that the service control plane is separated from the media bearer plane. Thus, the network resources can be fully shared, the equipment upgrade and service expansion are simplified, and the development and maintenance costs are reduced.
FIG. 1 illustrates the networking of an MGC and an MG. The MG communicates with the MGC over a media gateway control protocol. At present, the widely used protocols include the H.248/Gateway Control Protocol (MeGaCo) and Media Gateway Control Protocol (MGCP). In addition, H.248/MeGaCo is developed on the basis of MGCP.
Various resources on the MG are abstractly represented by terminations. The terminations are categorized into physical terminations and ephemeral terminations. Physical terminations represent some physical entities that exist semi-permanently, for example, a time division multiplexing (TDM) timeslot. Ephemeral terminations represent some public resources requested ephemerally and released after application, for example, a Real-time Transport Protocol (RTP) stream. In addition, a root termination is used to represent the entire MG. The correlations between terminations are abstractly represented by contexts. A context may include multiple terminations. Thus, a topology is used to describe mutual relationships between the terminations. A null context represents terminations that are not associated with other terminations.
In the prior art, the MGC instructs the MG to perform a resource operation through a signal, for example, playing and recording. A signal is executed on the termination or stream. If the signal is executed on the termination, the signal is applicable to all the streams on the termination. A signal list may be used to represent a series of operations that need to be performed in sequence. An interval may be available between each operation. The MGC adds the signal and/or signal list to a signal descriptor, and sends the signal descriptor to the MG. The signal and/or signal list in the signal descriptor sent at the same time is executed concurrently.
The signal execution duration on the MG is based on an earlier setting. In actual applications, this earlier setting may be adjusted. In the prior art, however, only the speed of the playing signal can be adjusted. For example, a preset segment of media may last 30 seconds at the default playing speed. In the media playing process, however, this segment of media may be required to last 45 seconds or be fast rewound to the beginning within 15 seconds, that is, it may be played in two ways at an adjusted speed relative to the default speed.
The prior art has at least the following weaknesses:
In the prior art, the signal execution duration can only be based on the earlier setting; during the signal execution, the MGC cannot adjust the speeds of signals other than the playing signal, thus failing to meet the instant adjustment requirement.